A VCUG, or voiding cystourethrogram, is a type of X-ray that tests for bladder and urethral abnormalities. VCUG mainly checks for ureteral reflux, which can lead to kidney damage. Infants, children and adults can have a VCUG test. Your test results tell your provider what kind of treatment you need.


What is a VCUG test?

A VCUG test, or voiding cystourethrogram, is a test that looks at the size and shape of your bladder and how well it fills and drains. Your bladder is an organ that holds your pee (urine). A VCUG test helps healthcare providers diagnose irregularities in your bladder and urethra, the tube that lets pee leave your body.

A VCUG uses contrast dye (fluid that shows up as a bright color on imaging tests) and X-ray to see if there are problems with how your urinary tract works. The X-ray allows your provider to take pictures of your bladder while it’s filling up with urine — which now contains the contrast dye — and emptying. This is how they can see the direction the liquid flows in and if there are any issues as the liquid leaves your bladder.

Normally, pee only flows one way: down into your urethra from your bladder. Then, it leaves your body. But sometimes, pee that was in your bladder can flow upward (in the wrong direction) into your ureters and to your kidney. This can result in kidney infections (pyelonephritis) which can lead to kidney damage and scarring.

A radiologist performs a VCUG in your provider’s office, a hospital or an outpatient imaging center. You’re awake for the test, and it may feel uncomfortable. A VCUG test lasts less than an hour and you can return to your normal activities right away.

Providers routinely perform VCUG in infants and children who have repeat urinary tract infections (UTIs), as chronic infections can affect their kidneys.


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What can a VCUG diagnose?

A VCUG shows your provider how your urinary tract functions.

One of the main conditions a VCUG diagnoses is ureteral reflux (also called vesicoureteral reflux). Ureteral reflux is when your pee flows from your bladder back into your ureters (tubes that connect your kidneys to your bladder) and kidneys, instead of exiting your body through your urethra. This can lead to kidney infections and frequent UTIs. VCUG is the most common test to diagnose ureteral reflux in children.

It can also diagnose disorders that lead to urethral strictures (narrowed areas) or other urethral obstructions, which may make it difficult for you to pee.

When does a person need a VCUG?

The most common reason to perform a VCUG is to diagnose ureteral reflux. This may happen when a person has:

  • Persistent urinary tract infections (UTIs).
  • A congenital condition (something you’re born with) that affects your urinary tract.
  • Urinary incontinence, narrowed urethra or an enlarged prostate (for people who have one).
  • Prior urethral trauma, infections or surgery.
  • A biological family history of urethral reflux.


Test Details

How is a VCUG performed?

The test involves a healthcare provider inserting a urinary catheter (a long, flexible tube) into your urethra and up into your bladder. Then, they push an iodine-based contrast dye through the catheter and into your bladder. The radiologist will take X-rays of the fluid inside your bladder to see what it looks like when it’s full. The catheter is then removed and they’ll then take X-rays of your bladder emptying to see where the contrast fluid goes.

How long does a VCUG test take?

The test takes about 30 to 45 minutes.

Does VCUG require sedation?

Sedation is rarely necessary for a VCUG. Some children may need sedation, though. If your child’s provider thinks sedation is a good idea based on your child’s medical history, they’ll talk to you about how to prepare for sedation.

How do I prepare for a VCUG?

Let your healthcare provider know about any medications you take and any allergies you have. They may ask that you stop taking certain medications in the days prior to a VCUG test. If you (or your child) may be pregnant, let your healthcare provider know.

It’s normal to feel some anxiety leading up to the test, especially since you’ll be awake. Let your healthcare provider know you’re feeling worried. They may be able to help ease your worries.

A parent or guardian is typically allowed to stay with their child if the child is the one getting a VCUG. Most healthcare providers recommend preparing your child before the procedure. Explaining exactly what will happen and that you’ll be with them the whole time are good ways to ease their anxiety. Answer their questions and provide clear and honest answers. Your child’s pediatrician may be able to help you determine how to best prepare them for the test. For young children, bringing a comfort item is recommended.

Since there’s no sedation, restricting food or beverages before the test isn’t necessary.

What happens during a VCUG?

A VCUG test generally follows these steps for both adults and children:

  1. Disrobe your lower body. You’ll remove your lower garments (such as pants or skirts) and undergarments. Your healthcare provider may give you a gown or sheet for cover.
  2. Lie down on a table on your back. People with penises will lay with straight legs. People with vaginas will lay in a frog or butterfly position (knees open and soles of the feet touching). This allows healthcare providers to have the best access to your urethra.
  3. A healthcare provider will wash your genital area with mild soap and water. They may put a special numbing gel on your urethra.
  4. A healthcare provider inserts a tiny, soft tube called a catheter into your bladder through your urethra (the hole you pee out of). This can feel uncomfortable or cause minor discomfort (an unpleasant feeling that’s less intense than pain), but it shouldn’t cause any pain. The tube connected to the catheter is taped to your thigh.
  5. The X-ray machine will move so it’s directly over your pelvic region. It won’t touch you.
  6. Your provider inserts a liquid through the catheter to fill your bladder. This liquid contains a contrast material that’ll clearly highlight your urinary tract on the X-ray image. It helps radiologists see how liquid flows in and out of your bladder.
  7. The radiologist takes X-rays to capture what your bladder looks like when it’s filling up.
  8. You may feel the urge to pee while your bladder is filling. It’s important not to pee until your bladder’s full and your provider tells you that you can pee. It may be difficult to prevent infants and young children from peeing.
  9. Once your bladder is full, the catheter will be removed and a radiologist will tell you that you can pee.
  10. For children, healthcare providers may allow them to pee into a cup, in a bedpan or directly onto the table (which has been covered in towels). As they do this, the radiologist will continue to take X-rays of their bladder emptying.
  11. If you’re an adult, your provider will ask you to pee in a bedpan or urinal once your bladder is full. A radiologist will continue to take X-rays as you completely empty your bladder.

It’s important to note that X-rays are taken both while your bladder is filling and while it’s emptying because reflux can happen at both stages. Your radiologist is there to help guide the process, so listen to their instructions while they conduct the test. If you’re accompanying your child, try to provide extra comfort to them during the filling and emptying steps. Letting them hold your hands or a comfort object may help, as well as distracting them with a positive, happy voice.

What should I expect after a VCUG?

You can go home right after a VCUG and return to your normal activities. You may feel a stinging or burning sensation when you pee for the next 24 to 48 hours. Drink lots of fluids and use the bathroom as soon as you feel the urge. This can prevent a urinary tract infection (UTI). It’s also normal to pee more often in the days following a VCUG. Your pee may be pink, but it should never be red.

If any of these symptoms last longer than 48 hours or if your pee is red, contact your healthcare provider.


What are the benefits of a VCUG?

The benefit of a VCUG is that it allows your provider to see how liquid flows through your urinary tract. It helps them diagnose conditions that, if left alone, could lead to kidney damage.

What are the risks of a VCUG?

A VCUG is a safe procedure, but there are minor risks. Some people can have a reaction to the dye if it goes into their bloodstream and not their bladder. But this is rare.

Your healthcare provider minimizes your exposure to radiation by placing a special blanket over you, but you’ll still have a tiny amount of radiation exposure. The benefit of an accurate diagnosis typically outweighs this risk. Pregnant people should let their healthcare provider know they’re pregnant before the test.

Some minor side effects of VCUG include:

  • Hot flashes.
  • Nausea or vomiting.
  • A burning sensation when you pee (for about 24 to 48 hours).
  • A UTI from your provider placing the catheter (this is rare).

Serious side effects could include:

  • Difficulty breathing.
  • Low blood pressure.
  • Swelling of your throat or mouth.

How painful is a VCUG?

It’s normal to feel some discomfort during a VCUG, especially when your provider inserts the catheter. Your bladder may also feel uncomfortably full and you may feel like you want to or need to pee. Some people feel anxious and nervous about a VCUG. This is also normal. Try to take long, deep breaths. It may help to bring a stress ball to squeeze or a picture of a loved one so that you can soothe or calm yourself.

A VCUG can be stressful for a child. Try to make every attempt to comfort them while also explaining to them that the test is necessary to help them. Ask your healthcare provider for specific tips if you’re unsure of how to handle the situation.

Results and Follow-Up

What do the results of a VCUG mean?

The test can show your healthcare provider if you have urethral reflux. It can also tell them if areas of your urinary tract appear normal or if they seem wider or narrower than usual.

Your radiologist may assign a score to your test results if they make a diagnosis of reflux. This is especially true if your child is the person who had a VCUG. The rating ranges from one to five, with one being mild and five being severe. Treatment may depend on how severe the reflux is and if it’s affecting your kidneys or ureters. Your healthcare provider will discuss treatment options with you based on your results.

When should I know the results of a VCUG?

A radiologist will interpret the images, write a report and deliver the results to your healthcare provider. It can take up to two days for this to happen. Check with your healthcare provider about when you can expect results.

If the results are abnormal what are the next steps?

Depending on what your healthcare provider finds, the next steps vary. Some people need treatment which could involve medications or surgery to fix any problems with their bladder or urethra. Other times, your provider may recommend lifestyle modifications to help you.

When should I call my healthcare provider?

Peeing more frequently and passing pee that’s slightly pink is normal after a VCUG. Feeling burning when you pee is also OK. If any of these symptoms lasts longer than 48 hours, contact your provider.

Pee that’s red, a fever or pelvic pain may be a sign of a problem. You should contact your provider if any of these things happen in the days following a VCUG.

Additional Common Questions

What is the difference between voiding cystogram and VCUG?

There’s no difference between a VCUG and a voiding cystogram. They’re the same test.

A note from Cleveland Clinic

VCUG is a diagnostic test that involves X-rays and contrast dye. It’s normal to feel stress in the days and hours leading up to a VCUG test. If your child is the person having a VCUG test, remember that they may also have anxiety and not know what to expect. Your test results will determine what the next steps are. Talk to your healthcare provider about any concerns you have before the test. They can help walk you through the test and possible outcomes.

Medically Reviewed

Last reviewed on 06/06/2023.

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